Automatic welding hood with automatically positioned eye shield

ABSTRACT

A welding hood having an electromechanical system for automatically opening and closing a hinged eye shield located thereon and for controlling energization of the welding gun at the beginning or end of a welding operation. On starting the welding process, a manually operated switch actuates a first solenoid valve which stops the flow of fluid to a piston connected to the eye shield, thereby allowing a spring providing an opposing force to move the eye shield to its protective position in front of the welding operator&#39;&#39;s eyes. The switch also actuates a second solenoid valve which allows an inert gas to flow through the welding gun. As the eye shield assumes its protective closed position, a microswitch is actuated along with a relay coil, completing a circuit allowing the welding gun to energize. Upon compeltion of the welding process, the eye shield automatically retracts so that the operator may view his work.

United States Patent Thomason et al.

[ Sept.'19, 1972 [54] AUTOMATIC WELDING HOOD WITH AUTOMATICALLYPOSITIONED EYE Primary Examiner-R. F. Staubly SHIELD Anomey-Newton,Hopkins & Ormsby A [72] Inventors: James P. Thomason, Jasper, Ga. Tl"

30143; Thomas Harold Jennings, [57] ABS CT 2640 Whitehurst Dr.,Marietta, Ga. A welding hood having an electromechanical system 30060for automatically opening and closing a hinged eye shield locatedthereon and for controlling energization [22] 1970 of the welding gun atthe beginning or end of a weld- [21] Appl.No.: 83,758 ing operation. Onstarting the welding process, a manually operated switch actuates afirst solenoid valve which stops the flow of fluid to a piston con- (g!g g z l siggg nected to the eye shield, thereby allowing a spring 58]Field "5 g 124 l26 providing an oppos ng force to move the eye shield to219 615; 138L144 its protectlve position in front of the weldingoperators eyes. The switch also actuates a second solenoid valve whichallows an inert gas to flow through the [56] References Cited weldinggun. As the eye shield assumes its protective NI STATES PA closedpolsition, almicroswitch is :fltuated :Long a re ay col comp etlng acircuit owing e we lng 2,761,046 8/1956 Herrick etal ..2l9/l47 gun toenergize Upon companion of the welding 3,501,613 3/ 1970 process, theeye shield automatically retracts so that the operator may view hiswork. 3:096:430 7/1963 Farr ..219/l47 lClaim,4 Drawing Figures e h '1 l0r 47' 1 4 5 H l II II H H II ll [I /ll 54 H H, 49 H 50 II F l V H 53 llL :=:L :A 52

PATENTEMU 19 I912 SHEET 2 BF 2 FIG 3 BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to welding hoods, and moreparticularly to welding hoods having automatic controls for opening andclosing an eye shield mounted thereon in conjunction with the startingand finishing of welding operations.

2. Description of the Prior Art Welding hoods including movable eyeshields positioned in front of the welding operators eyes are well knownin the art. Such eye shields generally comprise a forwardly protrudingupwardly hinged rectangular frame having mounted therein alight-filtering protective lens which is usually a piece of dark,opaque, or polarizing glass, plastic, or similar light-filteringmaterial. The glass in the eye shield is sufiiciently dark or opaque toprotect the operators eyes from sparks and intense light, while at thesame time transmitting sufficient light to allow him to view the weldingprocess. Such eye shields are especially necessary to protect the eyesfrom the intense glare and sparks produced by arc welding oroxy-acetylene welding. However, the very opaqueness of the mask is suchas to make viewing of the work difficult in the absence of a brightlight source such as the welding arc. Therefore, in order to view thewelding work when the welding torch is removed or turned off, it isnecessary that the light-filtering protective lens be removed from theoperators field of vision.

While such viewing may be achieved by removing the welding hood, this isan awkward and time-consuming method. Accordingly, many welding hoods inuse today are provided with hinged eye shields in order to allowmovement of the eye shield out of the operators field of vision withoutthe necessity of moving or removing the welding hood itself. Manydevices have been proposed in the prior art by which the eye shield canbe automatically moved from its-raised inoperative position out of theoperators line of vision to its closed protective position in front ofthe operators eyes and back again, in order to avoid the necessity ofmanual movements by the operator. Some of these systems employ voltagevariations in the electrical circuitry, utiliz ing various linkagesystems, as means by which switches in the welding circuit are kept openuntil the eye shield is moved into its protective position. With the eyeshield in its protective operative position, a welding circuit iscompleted and the welding operation can begin. Such systems haveheretofore been relatively complex and susceptible to malfunctioning.

Other prior art proposals have included systems which require thewelding process to first begin so that the welding electrode itself mayact as a contact, completing a circuit which by a suitable linkagesystem causes the eye shield to close to the protective position. Suchmethods are potentially hazardous to the operator, since the arc must beformed before the eye shield is placed in the protective position. Inaddition, systems have heretofore been proposed employing variousmechanical devices whereby the operator himself positions the eyeshield. These are disadvantages in requiring the use of a free hand,which the welding operator may not have conveniently available.

These and many other devices heretofore proposed, while theoreticallysatisfactory, have in actual use been often found to be cumbersome,expensive, and susceptible to malfunctioning in insuring that theprotective eye shield on the welding hood was closed to its operativeposition before the welding arc was formed. Even a slight amount ofunpredictability in the operation of such an eye shield creates adangerous safety hazard for the operators eyes, due to the extremelyintense light given off by the welding arc.

SUMMARY OF THE INVENTION An object of this invention is to provide awelders hood having an eye shield which will be automatically positionedproperly in front of the operators eyes at the beginning of the weldingoperations.

Another object of the present invention is to provide an eye shield on awelding hood which will insure that the welding process will not beginuntil the eye shield is in the closed operative position.

A further object of the present invention is to provide an eye shield ona welding hood which will be automatically positioned properly withrespect to the operators eyes regardless of movements of the operatorshead.

Yet another object of this invention is to provide an eye shield on awelding hood which is automatically moved to a raised inoperativeposition outside of the operators field of vision upon completion of thewelding process.

A still further object of this invention is to provide simple, safe, andreliable means for automatically controlling the proper positioning ofan eye shield on a welding hood.

The foregoing and other objects are obtained in accordance with thepresent invention which provides a welding hood having a uniqueelectro-mechanical system for automatically positioning an eye shieldmounted thereon between its protective closed position and itsinoperative raised position. A pivotally mounted eye shield is providedwith operative positioning means such as a spring tending to hold theeye shield in its protective closed position in front of the operatorseyes and perpendicular to his line of sight. A fluid cylinder mechanismis connected through a first solenoid fluid supply valve to apressurized fluid supply source which, when the valve is open, allowsthe cylinder mechanism to overcome the spring, causing the eye shield tomove to a raised inoperative position. A manually operated switchactuates the first solenoid fluid supply valve, closing the valve andthus stopping the flow of pressurized fluid to the fluid cylindermechanism. This permits decompression of the cylinder, thereby allowingthe spring to move the eye shield into its protective closed position. Asecond solenoid inert gas control valve is wired through the manuallyoperated switch in parallel with the first solenoid fluid supply valve.Upon triggering the manual switch, the second valve is simultaneouslyopened, allowing an inert gas mixture to flow to the welding gun. Whenthe eye shield has assumed its closed protective position, microswitchtriggering means mounted thereon actuate a microswitch and relay coil,completing a circuit allowing the welding gun to energize, and weldingoperations may begin.

Upon completion of the welding operations, the operator trips a switchto stop the flow of the welding gun energizing current. The cessation ofcurrent flow through the first solenoid fluid supply valve causes it toopen, allowing the pressurized fluid to again flow into the fluidcylinder mechanism. The now-pressurized fluid cylinder mechanismovercomes the spring, moving the eye shield to its raised inoperativeposition. As the eye shield pivots upwardly, the microswitch triggeringmeans deactivate the microswitch and relay coil, cutting off the currentflowing therethrough to the welding gun. Since the solenoid inert gascontrol valve is wired in parallel with the first solenoid fluid supplyvalve, current simultaneously ceases to flow therethrough, closing thevalve and cutting off the supply of inert gas to the welding gun.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features andadvantages of the invention will become more fully apparent to thoseskilled in the art from the following description of an illustrativeembodiment of the invention, as shown in the annexed Drawings, whereinlike reference characters designate like or corresponding partsthroughout the several Figures, and in which:

FIG. 1 is a schematic perspective view of a welder wearing a hood of thepresent invention, together with associated welding equipment;

FIG. 2 is a detailed perspective view of an eye shield mechanism of thepresent invention mounted on a welding hood;

FIG. 3 is a vertical cross-section taken through an eye shield andadjoining hood parts;

I FIG. 4 is a schematic diagram of a welding hood of the presentinvention as in combination with a welder and associated apparatus.

DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT While it will be understood bythose skilled in the art that with only minor variations the presentinvention may be used in oxy-acetylene welding and other types ofwelding, for purposes of simplicity in illustration, the followingdescription will be directed to an embodiment suitable for arc welding.Such an embodiment is schematically illustrated in FIG. 1, wherein awelding operator and the welding apparatus are depicted. As isconventional in the welding art, a hinged eye shield containing alight-filtering protective lens is mounted on a welding mask or hood 11,which is worn over the face of the welding operator. The operator isshown holding a welding gun 12, which may be of any suitable type. Aboom 13 guides a welding electrode 14 and fluid and electrical lines,generally depicted as numeral 15, which are necessary for the operationof eye shield 10. A suitable electrical power generator 16 supplieselectrical power for the welding process itself, as well as for theelectro-mechanical device of the present invention. A source of inertgas for the welding apparatus, and a source of gas or liquid fluid forthe eye shield mechanism are not shown, such sources being well known inthe art.

The welding hood 11 is of a type ordinarily used in the art, which restsupon the operators head or shoulders. As shown in FIGS. 2 and 3, thehoods provided with an opening in front of the operator's eyes, aroundwhich an eye shield supporting frame 17 is mounted. The supporting frame17 is mechanically secured to the welding hood 1] by suitable means,such as weld 17' or the like, and provides a hollow housing 18 therein.A clear safety lens 19 is supported vertically within the hollow housing18 by an inwardly extending flange 18' integrally formed on supportingframe 17. Safety lens 19 may be constructed of glass, plastic, or anyother suitable transparent material, and is clear rather than opaque inorder to protect the operators eyes from foreign objects. In front ofthe clear safety lens 19 and vertically mounted in the eye shield is alight-filtering protective lens 20, which is vertically supported by anysuitable supporting means, such, for example, as a lip 21 of the eyeshield frame. The light-filtering protective lens is generallyconstructed of opaque or polarizing glass, plastic, or other suitablematerial, as known in the art, and may be secured from the inside withinthe eye shield by any suitable means, such as a leaf-type springretainer shown at 22. While as previously stated, any suitable means maybe used to support the light-filtering protective lens in its verticalposition, the above construction is commonly used because it offers easyinterchangeability and replacement of the light-filtering protectivelens.

Hinge blocks 23 and 24 are secured to the top of the eye shieldsupporting frame 17 by welding or the like. The eye shield is hingedabout pins 26 and 26 to blocks 23 and 24 so as to allow movement withinroughly a arc, as shown at A, between a closed operative position 20 anda raised operative position shown in dashed lines at 101.

As best seen by reference to FIG. 2, microswitch triggering means suchas tabular protrusion 30 extend laterally and outwardly from the bottomouter corners of eye shield 10. When the eye shield is in its closedoperative position, protrusion 30 engages a movable contact 31 mountedon a microswitch S2, which is located on the outside of eye shieldsupporting frame 17. On the opposite side of the eye shield, a secondtabular protrusion 29 may be provided. Either protrusion allows theoperator to manually raise or lower the eye shield if he so desires.

In accordance with the present invention, a pivotally mounted eyeshield, for example, of the type shown comprising a forwardly protrudingrectangular frame pivotally mounted over a suitable opening in thewelding hood in front of the operators eyes and having a light-filteringlens and, if desired, a second clear safety lens mounted therein, isprovided with operative positioning means such as a spring 40, FIG. 3,which tends to hold the eye shield in its protective closed position infront of the operators eyes and perpendicular to his line of sight.Spring 40 is located within a fluid cylinder 28 having a piston rod 27extending outwardly therefrom. In the absence of a greater opposingforce, the spring maintains a piston head and associated rod 27 in theraised position shown in the Drawing. The end of the piston rod 27 islinked to eye shield 10 via a suitable lever arm 32. The lever arm isfixedly secured at the lower end of piston rod 27 by any conventionalmeans, such as nuts 33 and 34. The lever arm 32 is pivotally linked incam fashion to hinge block 23, FIGS. 2 and 3, by a connecting pin 35, topermit the desired pivotal rotation of the eye shield around theconnecting pin. The fluid cylinder mechanism is supported verticallyabove the eye shield by suitable mechanical securing means. In onesuitable arrangement, an L- shaped bracket 36 is secured at one end tothe welding hood 11 by bolt 37 and nut 38, and the L-shaped bracket issecured at the other end thereof to support the fluid cylinder 28 by athreaded cylinder cap member 39. A suitable sealing means, such asO-ring 41, sealingly secures piston head 42 of piston rod 27 within thefluid cylinder. The O-ring is generally disposed within an annulargroove around the outside of the piston head, as shown in FIG. 3. Asuitable threaded fluid fitting 43 is provided at the top of cylinder 28for connecting either a hydraulic or pneumatic fluid system thereto.Fluid line 44 supplies fluid through the fitting to cylinder 28 via asolenoid fluid control valve 45, as shown schematically in FIG. 4. Itwill be apparent that upon the introduction of pressurized fluid, thepiston will be forced downwardly, compressing the spring 40 therein. Inthe absence of a pressurized fluid supply, the spring 40 will maintainthe piston in its raised position, thereby maintaining the eye shield inits closed operative position. With the eye shield in its operativeorclosed position, the fluid supplied to cylinder 28 is ofi', and leverarm 32 is in its raised position, with the connecting pin 35 disposedupwardly and rearwardly to pivotal connecting pin 26, located centrallyin hinge block 23. When piston 27 is compressed by reason of fluidpressure supplied from fluid line 44, lever arm 32 is forced downward bythe downward movement of piston rod 27, thereby pivoting the eye shield10 upwardly through a roughly90 degree are to the open inoperativeposition, indicated at 101. With the eye shield in the inoperativeposition, the connecting pin 35 appears at a location downward andrearward of connecting pin 26 of hinge block 23, as shown in FIG. 3.

It will be apparent to those skilled in the art that any suitable designmodification may be utilized which will effectively provide opposingforces tending to open or close the eye shield. Thus, it will beapparent that there is no necessity for locating the operativepositioning means such as spring 40 within the fluid cylinder. The sameeffect may be obtained by mounting it in opposition to the fluidcylinder on the side of eye shield supporting frame 17. Other suitablearrangements will be readily apparent to those skilled in the art.

A suitable wiring arrangement for the electromechanical system of thepresent invention in combination with a conventional welding apparatusis schematically illustrated in FIG. 4. As shown therein, a suitableelectrical power source 46 is provided within a standard weldinggenerator 16. A power source of only 24 volts is sufficient to operatethe device of the present invention. Located on the welding gun 12, orprovided as a foot switch (not shown), a manually activated switch S1 isoperated by pressing a trigger 47, actuating movable contact 48 andthereby closing the switch. This operation is performed when the weldingoperator desires the welding process to begin. A wound coil 49 ofsolenoid fluid control valve 45 is electrically connected to switch S1.The solenoid fluid control valve 45 is preferably located on the weldingboom 13, as shown in FIG. I, in order to keep it free from the weldingwork area. This valve connects fluid line 44 with a pressurized fluidsupply source 50. As previously mentioned, the fluid may be eitherhydraulic or pneu matic. Fluid line 44 and electrical wires 51 are shownin FIG. 1 supported by the welding boom 13 so as to be kept out of theoperator's way. They may, as illustrated at 15 in FIG. 1, be springcoiled in order to keep them in the clear. I

Wired in series with solenoid fluid control valve 45 is a wound coil 53of a solenoid gas purge valve 52. When open, this valve permits an inertgas mixture, such as argon, argon-carbon dioxide, or the like to passfrom a supply source (not shown) through the welding gun 12 via gas line54. The-solenoid gas purge valve 52 may also be located on welding boom13, if desired.

When the protective eye shield has been moved to its closed operativeposition, the movable contact 31 on switch S2 located on the side of thesupporting frame 17 is closed, completing a circuit from the switch S2to the main welding power source located within the welder 16.

To summarize the operation of the device in accordance with the presentinvention, the operator presses trigger 47 on the welding gun,contacting movable contact 48 which closes switch S1. As switch S1 isclosed, electrical current flows to coil 49 of solenoid fluid controlvalve 45, closing the valve to stop the flow of pressurized fluidthrough fluid line 44. The cessation of fluid flow permits decompressionof piston 27 by opposing operative positioning means, such as the springshown, thereby allowing the piston to return to a raised position withincylinder 28. As the piston rises, the lever arm 32 which connects pistonrod 27 with eye shield 10 also rises, causing the eye shield to pivotapproximately from its inoperative open position 101 to its operativeclosed position parallel to the surface of the welding hood, shieldingthe operators eyes.

At the same time, closing of switch S1 energizes coil 53 of solenoid gaspurge valve 52, opening the valve. Inert gas flows along gas line 54 tothe welding gun 12 prior to the actual welding process.

As the eye shield assumes its closed operative position, switch S2 isclosed by forcing contact 31 into a closed position. This allows currentto flow through relay coil 55, which is energized by the increasedvoltage therein, allowing the current to flow back to power source inthe welder 16, thereby completing the electro-mechanical circuit. Uponcompletion of the circuit, the main welding current begins to flow andthe operator may begin welding operations.

When the operator has completed welding, the operation is reversed.Release of trigger 47 deactivates movable contact 48, stopping the flowof main welding current by opening switch S1. Current thus ceases toflow through coil 49, causing the solenoid fluid control valve 45 toopen. With this valve open, hydraulic or pneumatic fluid may flowthrough fluid line 44 to compress piston 27. This compression overcomesthe operative positioning means, lowering the piston. Lever arm 32,which is attached to the piston rod, acts as a cam, causing the pivotalupward rotation of eye shield 10 around connecting pin 26 in hinge block23. The eye shield thus pivots upwardly approximately 90 to theinoperative raised position shown at 101 in FIG. 3. As the eye shieldpivots upwardly, the protruding tab 30 on the outside frame thereofdisengages switch S2. The switch thus opens, and current ceases to flowthrough relay coil 55 and power source 46. Simultaneously, the openingof switch S1 cuts off current flow through coil 53. The solenoid gaspurge valve 52 thus closes, cutting off the supply of inert gas to thewelding gun.

It will be apparent that the device of the present invention does notallow flow of the main welding current until the solenoid fluid valve 45has been closed, thereby causing the piston 27 to move the eye shield 10to its operative position 101. As this operative position is assumed,contact is made with switch S2, along with relay coil 45, completing theelectrical circuit and allowing flow of the main welding current.Because the main welding current cannot flow unless the eye shield is inits operative position, this avoids a safety hazard to the operator,since welding current will flow only when the protective eye shield isoperatively positioned in front of his eyes. When welding operationshave ceased, the eye shield is automatically raised out of the operatorsline of sight, thereby allowing him to inspect his work. These functionsare performed automatically, and therefore do not require any attentionor extra steps to be taken by the operator. Thus, a safety hazard hasbeen eliminated without introducing any additional activity on the partof the operator.

It will be appreciated that while the foregoing disclosure relates onlyto an illustrative embodiment of the invention suitable for use in arcwelding, it is capable of generator for ignition of the oxy-acetylenemixture upon closure of the electro-mechanical system. Accordingly,these and numerous other modifications or alterations may be made bythose skilled in the art without departing from the spirit and scope ofthe invention as set forth in the appended claim.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. A welding system comprising a welding means, an electric circuit forcontrolling the operation of said welding means, a welding hood havingan eye shield mounted thereon, said shield being movable between anoperative position in the line of sight of a welder wearing said hoodand an inoperative position removed from such line, a switch mounted onsaid hood and controlling the circuit for said welding means, meansconnecting said switch with said eye shield in such a manner that theswitch will be closed when the shield is in operative position and openwhen the shield is in inoperative position, whereby the welding meanswill be rendered inoperative unless the shield is in operative position;means for moving said eye shield between its operative and inoperativepositions, comprising a cylinder, a piston therein operatively connectedto said eye shield, a sprin ur 'ng said piston toward a position inwhich said eye s re d 18 in operative position, means for supplyingfluid to said cylinder to cause the piston to move against the action ofthe spring, thereby moving said eye shield to inoperative position, avalve for controlling said fluid supplying means, means for supplying aflow of inert gas to said welding means, a valve for controlling thesupply of such gas, solenoid means connected with both said valves andadapted, in one position to simultaneously close the valve controllingthe supply of fluid to said cylinder and open the valve controlling thesupply of inert gas and in another position to open the former valve andclose the latter valve, and a switch for controlling the supply ofcurrent to said solenoid means II! I

1. A welding system comprising a welding means, an electric circuit forcontrolling the operation of said welding means, a welding hood havingan eye shield mounted thereon, said shield being movable between anoperative position in the line of sight of a welder wearing said hoodand an inoperative position removed from such line, a switch mounted onsaid hood and controlling the circuit for said welding means, meansconnecting said switch with said eye shield in such a manner that theswitch will be closed when the shield is in operative position and openwhen the shield is in inoperative position, whereby the welding meanswill be rendered inoperative unless the shield is in operative position;means for moving said eye shield between its operative and inoperativepositions, comprising a cylinder, a piston therein operatively connectedto said eye shield, a spring urging said piston toward a position inwhich said eye shield is in operative position, means for supplyingfluid to said cylinder to cause the piston to move against the action ofthe spring, thereby moving said eye shield to inoperative position, avalve for controlling said fluid supplying means, means for supplying aflow of inert gas to said welding means, a valve for controlling thesupply of such gas, solenoid means connected with both said valves andadapted, in one position to simultaneously close the valve controllingthe supply of fluid to said cylinder and open the valve controlling thesupply of inert gas and in another position to open the former valve andclose the latter valve, and a switch for controlling the supply ofcurrent to said solenoid means.